Machines which utilize blades to grind or otherwise cut food items such as ice or the like are most often required to provide safety features to prevent injury to the user. Typical of such machines is an ice shaving and dispensing machine such as shown in U.S. Pat. No. 6,194,013. In these devices, the blade components are positioned at the bottom of a bin which is adapted to receive a supply of ice which is to be shaved and which has a cover.
Because the blade and other blade components could do serious damage to the hands of the user of the machine, most safety regulations currently require that the blade assembly be inoperable if the cover is removed from the bin. To that end, the unit is typically provided with a safety switch which disconnects the power to the blade assembly when the cover is removed. However, such switches have not totally been reliable and otherwise present problems for the unit. For example, if the switch is otherwise able to survive the hostile environment encountered in an ice shaving bin, it is nevertheless susceptible to falsely shutting off the power from the blade assembly. Such might occur, for example, when a bin full of ice being shaved would exert an upward force on the cover as the ice forms bridges and the like in the bin. This upward force could cause the cover to be sufficiently displaced such that the switch turns off the blade assembly at a time when it should be operating.
In addition, there are other detriments to the current safety switch devices. Oftentimes, the owner of a machine such as shown in U.S. Pat. No. 6,194,013 sees a need to increase the capacity of his ice bin. Rather than buying an entirely new unit, the user could position a capacity extending skirt on the open top of the bin and then place the cover on that skirt. However, such would permanently open the safety switch, rendering the blade assembly inoperable, and thus, if the owner wants addition capacity, he must either purchase a new unit or somehow reposition the safety switch to account for the new height of the bin.